improvement in piston-packing



i PIVFENT OFFICE.

OLIVER C# SMITH, OE SALEM, MASSACHUSETTS.

IMP'ROVEMENT |N PlsToN-PACKING.

Specification forming part of Letters Patent No. 35,267, dated May 13,1862.

To @ZZ whom timmy concern.'V

Be it known that I, OLIVER C. SMITH, of Salem, in `the county of Essexand State of Massachusetts, have invented a new and useful Improvementin Piston-Packing; and I do hereby declare that the following is a full,clear, and exact description of the same, reference being had to theaccompanying drawings, forming part of this specification, in whichFigure 1 is an axial section of a piston. with my improved packing. Fig.2 is aview of the interior of the same as exposed to view on the underor back side by the removal of the cap `or follower, spring, andexpanding cone.

Similar letters of reference indicate corresponding parts in the twofigures.

This invention consists in the employment, for pressing out thepacking-rings, of a series of arc-formed expanding pieces fitted to theinterior of `the rings, a hollow cone fitted to the hub of the pistonand to the interior of the arc-formed expanding pieces, and a springcoiled round the hub between the cone and the cap or follower of thepiston, the whole combined and operating, substantially as herein afterspecified, to produce an outward pressure against theinterior of therings, for the purpose of holding them in contact with the cylinder andcompensate for wear.

To enable others skilled in the art to make and apply myinvention, Iwill proceed to describe its construction and operation.

A is the head of the piston, having cast with it the central hub, B, andsecured firmly to the rod C.

I) is the cap or follower fitted to the rod C and secured against thehub B by a nut, E, screwing onto a screw-thread, a, cut on the rod. Theopposite faces of the head A and cap D are turned to present planesurfaces perpendicular to the axis of the rod, andthe exterior of thehub B is turned to a cylindrical form concentric with the rod.

F 'E F are the arc-formed expanding pieces, three or more n number,(three represented,) combining to form a divided ring, the exterior ofwhich is of cylindrical form of a circumference as much smaller than thebore of the cylinder as to leave room outside of it for thepacking-rings G G. The edges of the expanding pieces are faced to fitbetween the iiat inner faces of the head and cap, and the interiors ofthe said rings are turned out in conical form The conical faces b b l)are shown in Fig. 2. H is the expanding cone, bored to fit and slideupon the cylindrical exterior of the hub B, and having its exteriorturned to fit the conical inner surfaces of the arc-formed expandingpieces F E F.

I is the expanding-spring, of conical volute form, applied between thebase of the cone II" and the cap D, and secured in place and compressedto asuitable degree by the cap. The

pressure of the spring I upon the cone H tends to force it toward theheadA and against the conical surfaces bh b of the arc-formed expandingpieces F E F, and so tends to force outward the expanding pieces againstthe rings G Gl and press the rings outward against the inner surface ofthe cylinder. This outward pressure against the rings being constant,keeps them out against the cylinder, compensating for wear and keepingthe piston steam-tight.

VVhat I claim as my invention, and desire to secure byLetters Patent,is-

The combination, with the head A, cap C, and packing-rings G G, of thearc-formed expanding pieces F F E, the cone H, and spring I, the wholearranged, applied, and operating substantially as herein specified. u

O. C. SMITH.

lvitnesses:

JAMES LAIRD, EDw. W. HoDcsoN.

